1. Field of the Invention
The present invention relates to an electric stapler and an operation method of the electric stapler, and more particularly to an electric stapler for performing binding processing by implementing a paper bundle pinching step, a staple separation step, a penetration step, a clinch step and a paper bundle releasing step, and a motor driving method in the electric stapler.
2. Background Art
An electric stapler for penetrating a staple into a bundle of a plurality sheets of paper (hereinafter called a “paper bundle”) and binding the paper bundle by electric power is known conventionally (for example, see Patent Reference 1, Patent Reference 2 and Patent Reference 3).
[Patent Reference 1] JP-A-2001-191265
[Patent Reference 2] JP-A-8-187681
[Patent Reference 3] JP-A-2006-116638
FIG. 7 is a perspective view showing one example of the electric stapler. A driver unit 3 for forming and driving a staple is mounted inside of a front end of a frame 2 of the electric stapler 1. A clincher arm 4 upward and downward movably attached to the frame 2 is disposed in the frame 2. A table part 10 including a clinch device 5 of a flat clinch type is disposed in a top of the clincher arm 4.
A staple cartridge 6 is loaded into the frame 2 from upper side. Staple sheets in the staple cartridge 6 are fed one by one by a feeding mechanism (not shown) to a position of a forming plate and a driver 7 which are located in a forward side. A staple at a leading end in the staple sheet is folded into U-shape by the forming plate and is further fed to a position located just above the driver 7. When sheets of paper is inserted between the driver unit 3 and the table part 10, the clincher arm 4 moves downward and the sheets of paper are pinched by the driver unit 3 and the table part 10. Then, the driver 7 upward moves and the staple at the leading end is separated from the staple sheet. The driver 7 moves further upward and legs of the staple are driven in the sheets of paper. Then, the clinch device 5 is actuated and both of the legs of the staple penetrating the paper bundle are inward folded by the clinch device 5 and binding processing of the paper bundle is completed.
The general electric stapler 1 is provided with a plurality of swinging arms (the clincher arm 4 is also one of the swinging arms) for converting rotational motion of a main driving gear into upward and downward reciprocating motion with respect to the main driving gear rotated by driving a motor. During one rotation of the main driving gear driven by the motor, upward and downward movement of the table part 10 by actuating the swinging arms, forming processing, driving of the staple by the driver unit 3, clinch processing by the clinch device 5, etc. are executed.
Concretely, a paper bundle pinching step of pinching the paper bundle by downward moving the table part 10, a staple separation step of folding the staple at the leading end in the staple sheet in the U-shape by the forming plate and also separating the folded staple from the staple sheet by upward moving the driver 7, a penetration step of penetrating the staple into the paper bundle by the upward moving driver 7, a clinch step of inward folding the legs of both sides of the staple penetrating the paper bundle by the clinch device 5, and a paper bundle releasing step of releasing the pinched paper bundle by upward moving the table part 10 are executed during the one rotation of the main driving gear rotated by the motor, and binding of the paper bundle is completed by this operation of one cycle.
Further, demand for a reduction of noise occurring at the time of the binding processing is now increasing, in the electric stapler in which the binding processing as described above is performed. As a method for reducing the noise of the electric stapler, a driving speed of a motor may be uniformly reduced. However, for example, if the electric stapler designed to be driven by a voltage of 24 V is driven by a voltage of 12 V so that the driving speed of the motor is uniformly decreased, a reduction in penetration performance at the time of penetrating the staple into the paper bundle, a reduction in clinch force necessary for processing for clinching the legs of the staple, etc. occur so that there was a problem that binding performance (the bindable number of sheets, etc.) in the electric stapler may be reduced.
On the other hand, a method for adopting a high-performance motor including high torque characteristics even for low-speed rotation is also contemplated in order to decrease the driving speed of the motor while preventing the reduction in the penetration performance of the staple or the reduction in the clinch force in the clinch processing. However, when the high-performance motor is used, a price of the electric stapler rises and also the number of products increases as a kind of motor increases and there was a problem that management cost or component cost may increase. Also, a method for disposing a gear box or a belt variable speed mechanism is contemplated, but there was fear that the price rises and the number of products increases similarly.
Further, a method for preventing the noise from being propagated to an outside by accommodating the whole electric stapler in a soundproof box etc. is contemplated, but there was a problem of causing upsizing of an external form of a product.